As a dozen delegations sat inside the U.N. headquarters in Geneva on Saturday, drafting a plan to end the bloody Syrian crisis, a large funeral procession made its way through a Damascus suburb, clapping and chanting loud slogans against the government.

The man they were burying was wrapped in a Syrian revolutionary flag and had allegedly been killed by government forces. The crowd waved additional flags and shouted for freedom.

Then there was a deafening explosion.

In what opposition activists say was a government-organized car bombing, 85 people were killed and more than 300 people were wounded, most of them in critical condition.

Activists posted videos to YouTube purportedly showing the moment of the bombing in Zamalka and its aftermath.

After the loud crack and orange flash of the explosion come moaning and screams of "Allahu Akbar" ("God is great") from every direction. As the brown dust clears, the carnage becomes visible: charred bodies, missing limbs, people cradling the wounded or helping them to their feet, and pools of blood.

The flag-wrapped body of the funeral victim was lying on the ground.

Syrian opposition members say it was a car bomb timed to hit the procession in front of the mosque.

An activist named Bassem, who spoke to CNN from a suburb near Zamalka, said snipers in army uniforms began firing on people in the morning, and that plain-clothed government "thugs" even went to the funeral.

The security forces even fired on the crowd in the bombing's aftermath, killing a doctor who was trying to help the wounded, said Bassem, who asked that his last name not be used.

The opposition Local Coordination Committees of Syria said the scores dead in Zamalka were among 174 people killed across the country Saturday.

CNN cannot independently confirm the reports of casualties or violence because Syria restricts access by international journalists.

At almost the same time the bombing happened in Zamalka, members of the international community forged their most specific plan to date on how to deal with the violence that has raged in Syria ever since the uprising began there last year.

Former U.N. Secretary-General Kofi Annan called the meeting in his role as the special envoy for Syria, representing both the United Nations and the League of Arab States. Annan drafted a six-point peace plan for Syria more than three months ago, detailing steps for all sides to take, but it has yet to be implemented.

Those at the Geneva meeting agreed that the first step should be a recommitment to a cease-fire by both sides and implementation of Annan's plan without waiting for the actions of others, Annan said.

A key to the process will be a transitional government, which Annan said could include members of the current Syrian regime. That makes it possible for President Bashar al-Assad to be a part of the transition, but Annan pointed out it is the Syrians who will decide the make-up.

"I think people who have blood on their hands are hopefully not the only people in Syria," Annan said after the meeting. "I think the government will have to be formed through discussion, negotiations, and by mutual consent. And I will doubt that the Syrians -- who have fought so hard for their independence, to be able to say how they're governed and who governs them -- will select people with blood on their hands to lead them."

U.S. Secretary of State Hillary Clinton said the plan also makes clear the Syrian president cannot stay in power.

"Assad will still have to go. He will never pass the mutual consent test, given the blood on his hands," she said.

The agreement also calls on the Syrian government to release detainees and allow journalists access to the country. The right to peaceful demonstrations must be respected, Annan said.

Clinton said it is significant that all of the countries at the meeting were able to come to an agreement.

"Every day that has gone by without unity on the Security Council and among the states gathered here is a day that has given comfort to Assad and his cronies and supporters. What we have done here is to strip away the fiction that he and those with blood on their hands can stay in power," she said.

Clinton said the the U.N. Security Council should endorse the plan, thus allowing the possibility of sanctions against Syria if the requirements aren't met.

Russian Foreign Minister Sergey Lavrov said that the document should not be interpreted as outside powers imposing a transitional government on the Syrians. That process, he said, must come from inside Syria.

Annan was the one who called Saturday's meeting, inviting top diplomats from the five permanent members of the U.N. Security Council and envoys from Turkey, the United Nations, the European Union and the Arab League.